Re-enable TestEventInContext

https://codereview.chromium.org/2253973003 is landed. The V8
macro can be changed accordingly now and the test can be enabled
again.

BUG=647986

Review-Url: https://codereview.chromium.org/2360083005
Cr-Commit-Position: refs/heads/master@{#39636}

src/tracing/trace-event.h

@@ -280,7 +280,7 @@ extern TRACE_EVENT_API_ATOMIC_WORD g_trace_state[3];
     uint64_t cid_;                                                         \
   };                                                                       \
   INTERNAL_TRACE_EVENT_UID(ScopedContext)                                  \
-  INTERNAL_TRACE_EVENT_UID(scoped_context)(context.raw_id());
+  INTERNAL_TRACE_EVENT_UID(scoped_context)(context);
 
 #define TRACE_EVENT_RUNTIME_CALL_STATS_TRACING_ENABLED() \
   base::NoBarrier_Load(&v8::internal::tracing::kRuntimeCallStatsTracingEnabled)

test/cctest/test-trace-event.cc

@@ -257,10 +257,6 @@ TEST(TestEventWithId) {
   i::V8::SetPlatformForTesting(old_platform);
 }
 
-/*
-TODO(chiniforooshan, crbug.com/647986): enable this again after landing
-https://codereview.chromium.org/2253973003
-
 TEST(TestEventInContext) {
   v8::Platform* old_platform = i::V8::GetCurrentPlatform();
   MockTracingPlatform platform(old_platform);
@@ -284,4 +280,3 @@ TEST(TestEventInContext) {
 
   i::V8::SetPlatformForTesting(old_platform);
 }
-*/